Properties of the NaSSA and NARI class of drugs
Mirtazapine is a new antidepressant that enhances both noradrenergic and serotonergic activity and is currently the only member of the noradrenergic and specific serotonergic antidepressant (NaSSA) class. It exerts its effects by blocking α2 auto- and hetero-receptors, which results in enhanced release of noradrenaline from noradrenergic terminals and increased 5-HT release from serotonergic terminals. The increase in 5-HT transmission is specifically mediated via 5-HT1 receptors, as mirtazapine selectively antagonises 5-HT2 and 5-HT3 receptors. The most common side effects are sedation (H1 histamine receptor block) and increased appetite with weight gain. Dry mouth is also common, but other anticholinergic features such as blurred vision and urinary retention are not, suggesting a symapthomimetic effect. Reboxetine exhibits specificity for inhibiting the noradrenaline re-uptake transporter and is known as a noradrenaline re-uptake inhibitor (NARI). Common side effects seen with reboxetine are atropine-like side effects (sympathomimetic effect) and allergic rashes.
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References
Newer antidepressants: NRIs, SNRIs, NaSSAs and others. Gaskell publications, The Royal College of Psychiatrists. www.rcpsych.ac.uk/publications/gaskell/samplechaps/usedrugs5Chap.pdf accessed on 12 February 2003.
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